Python py3-validate-email None

Я хотел использовать py3-validate-email для проверки подлинности email:

from validate_email import validate_email
is_valid = validate_email(email_address='[email protected]', check_format=True, check_blacklist=True, check_dns=True, dns_timeout=10, check_smtp=True, smtp_timeout=10, smtp_debug=True)
print(is_valid)

Но получил:

02:29:30.265634 send: 'quit\r\n'
02:29:30.265896 connect: to ('alt3.gmail-smtp-in.l.google.com', 25) None
02:29:40.275959 send: 'quit\r\n'
02:29:40.276307 connect: to ('alt4.gmail-smtp-in.l.google.com', 25) None
None
02:29:50.284531 send: 'quit\r\n'